Merriam-Webster defines an assumption as “a fact or statement taken for granted.” We all make assumptions about a lot of things. Occasionally our most deeply held beliefs might be better described as assumptions. Some assumptions turn out to be true. But sometimes our assumptions turn out to be false.

Most Christians have assumptions about the Bible, what kind of book it is, how God speaks or doesn’t speak through it, and how we are to read it. Some assume the Bible is simply the words of mortals reflecting upon their faith in God. Others assume the Bible is the Word of God and that God chose every word the biblical authors used, and that the Bible is completely without error, at least in the original documents. Still others assume that the Bible was written by people who were influenced by the Spirit, yet, like all of us, also shaped by their own cultural and theological assumptions.

Many Christians today base their assumptions about the Bible on a verse of scripture found in 2 Timothy 3:16, “All scripture is inspired by God.” Yet their understanding of this verse is built upon more assumptions.

What did Paul mean by all scripture? Did he mean all the books now in our Bible? Most of the New Testament books had not even been written yet. Did he mean all the books of the Old Testament? The Jews were still not in complete agreement when he wrote as to which books constitute the sacred writings. Did Paul mean every word of scripture, or only the key ideas, or something in between? However you answer these questions, you’re making assumptions because Paul never clarifies this.

When Paul said that these writings were “inspired by God,” what did he mean? Paul doesn’t say what he meant by “inspired.” Further, Paul appears to have created the word himself. “Inspired” is a compound word in Greek, theo-pneustos, made up from the Greek words for "God" and "breathe." The word appears nowhere else in the New Testament, nor in the Greek language until after the time of Paul. Some assume it meant that God virtually dictated the Bible. Others assume that God is the inspiring subject of scripture. Still others believe that by “inspiration” Paul was describing the Spirit’s influence upon the biblical authors, an influence that did not entirely override their own cultural and theological assumptions.

Our debates in the church about thorny issues like homosexuality are really debates about our assumptions concerning the Bible. If every word of scripture was chosen by God, then there may be little room to question anything we read in the Bible. But if God influenced the human authors while not eliminating all trace of their own assumptions about God, morality, and science, then there may be room to ask questions of some of what we read in the Bible, particularly when those things stand in contrast to the picture of God we see in Jesus Christ.

Most biblical authors assumed that the earth was flat and that the sun revolved around the earth. They assumed that illnesses like epilepsy were caused by demons. The biblical authors assumed that slavery was morally acceptable to God. A common assumption of late Bronze and Iron Age people was that the gods were warriors who at times called their followers to put the entire population of enemy cities to death as a kind of offering, an assumption the early biblical authors seemed to share. Women were assumed to be subordinate to men. The biblical authors assumed that having multiple wives and concubines was morally acceptable, even for its greatest leaders.

If we question any of these things are we rejecting the Bible? Is it a lack of faith on our part when we wrestle with these kinds of passages? Or is it because we have faith, and we value the Bible, that we feel we should question those parts that are inconsistent with, among other things, the portrait of God revealed in Jesus Christ?

In the first half of my new book, Making Sense of the Bible: Rediscovering the Power of Scripture Today (HarperOne, 2014), I invite readers to question their assumptions about the Bible. In the second half of the book I consider a number of the perplexing passages of scripture, and I suggest that at least some of these tell us more about the cultural, theological, and ethical assumptions of the time in which the Bible was written than they tell us about the God whom the biblical authors sought to make known.